This disclosure relates to a volatile memory device, and more particularly, to a volatile memory device performing a self-refresh, and a memory controller used with the volatile memory device performing a self-refresh.
Volatile memory device, such as dynamic random access memory (DRAM), is refreshed periodically to prevent loss of data. A self-refresh mode refers to a mode in which the volatile memory device is refreshed through a timer to reduce power consumption. When the volatile memory device is in the self-refresh mode, an external controller does not know the state of the volatile memory device. Thus, external controller may send a self-refresh exit command to the volatile memory device to exit from the self-refresh mode, stand by for a predetermined time, and then output a valid command. Latency after the self-refresh exit command typically increases with an increase in a capacity of the volatile memory device. Therefore, the latency of the volatile memory device may need to be reduced.